This invention relates to a vision tester, in general, and, more particularly, to a device for use by a consumer in testing his near vision to determine the strength of non-prescription reading glasses the consumer requires.
It is now a common practice to sell non-prescription reading glasses directly to the consumer at pharmacies and other retail outlets. The non-prescription reading glasses are displayed in a retail establishment on free-standing displays.
Typically, a consumer selects a pair of non-prescription reading glasses from the display by trying on a number of pairs until he locates a pair that is suitable, from the standpoint of comfort, magnifying ability and appearance. In order to determine the appropriate magnifying ability for the reading glasses, charts are placed on the displays for the reading glasses. The charts have increasing sizes of print, and the purchaser of the reading glasses is instructed to stand approximately 14 inches (35.6 cm.) from the chart. When viewing the chart, the consumer will look at each line of print, and note the first line of print that appears to be out of focus. By reading across the chart, the consumer can then determine the amount of magnification needed for the reading glasses. The amount is expressed in diopters, an optical unit of measurement.
Once the consumer determines the appropriate amount of magnification needed, the consumer will then view all of the glasses on the display rack that have lenses at the appropriate diopter rating. The consumer can then select a pair of reading glasses which the consumer finds to be attractive and comfortable.
Although the use of the charts can effectively determine the proper amount of magnification needed for the reading glasses, it has been found that the use of the charts is imprecise. Quite often, the consumer will not stand an appropriate distance from the chart and, accordingly, consumers test the reading glasses by simply trying on a large number of reading glasses, of different magnifications, and testing them in connection with reading matter that is hand held by the consumer. The consumer will not always replace the reading glasses that have been tried on in the proper place on the display rack, and eventually, the reading glasses on the display rack are in total disarray.
A hand-held vision tester for non-prescription reading glasses is shown in U.S. Pat. No. 5,486,879. However, that vision tester suffers from a number of disadvantages. It includes a closed tunnel, with a plate at one end of the tunnel having indicia thereon. The plate is light permeable, and the indicia can only be read when the device is positioned in front of a light.
The device of the instant invention exposes the rear wall containing the printed material used for testing vision to the ambient light. There is no tunnel on which the rear wall is mounted.
Another advantage of the instant invention, as compared to that shown in U.S. Pat. No. 5,486,879, is that the degree of magnification for each lens is the same for both the right eye and left eye. In U.S. Pat. No. 5,486,879, the lenses are adjustable independently of each other. If one lens should indicate a certain power of magnification for the left eye and the lens for the right eye indicates a different power of magnification, the device is inappropriate for non-prescription reading glasses. All non-prescription reading glasses contain lenses of the same degree of magnification. In the instant invention, the lenses are arranged to be certain that the same degree of magnification will be used for both eyes. It is not possible to have different degrees of magnification for each eye.
Another advantage of the instant invention is that it is formed as part of a display rack for non-prescription reading glasses. This permits the consumer to test her vision at the same location as the location of the non-prescription reading glasses. Since the vision tester is formed as part of the display rack, there is little likelihood of damage caused by dropping or mishandling, as could occur with the hand-held vision tester of U.S. Pat. No. 5,486,879.
The device of this invention will precisely measure the magnification power necessary for the reading glasses of each consumer. By utilizing the device, the consumer can accurately determine the appropriate diopter rating for the reading glasses, and try on only those reading glasses having that diopter rating. Since the reading glasses will be removed from only one segment of the display, there is a much greater probability that the reading glasses will be returned to that segment after they are tried on, if they are not purchased.